Chen Mingliang, Zhang Guiying, Yi Mei, Chen Xiao, Li Ji, Xie Hongfu, Chen Xiang
Department of Dermatology, Xiangya Hospital, Central South University, Changsha 410008, China.
Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2009 Aug;34(8):705-11.
To investigate the effect of different dosages of ultraviolet A (UVA) on the proliferation and inducible nitric oxide synthase (iNOS)/nitric oxide (NO) system of human skin fibroblasts and to study the mechanism of skin photoaging.
Fibroblasts from normal skin cultured in vitro were irradiated with 1, 5, and 10 J/cm(2) of UVA, respectively. The proliferation activity, expression of iNOS mRNA/protein and NO production of human skin fibroblasts at different time points after irradiation of different dosages of UVA were measured by MTT assay, RT-PCR, Western blotting, and Griess reaction, respectively.
The survival rate of normal fibroblasts with time increase during 72 h. Low level of iNOS mRNA/protein expression and NO production was detected in normal human skin fibroblasts. But at each time point after 5 and 10 J/cm(2) dosage of UVA, the decrease of cell survival rate and the increase of iNOS mRNA/protein expression and NO production became more significant than those in the control group at the same time and 1 J/cm(2) UVA-irradiated group. There were significant differences (P<0.01 or P<0.05), which were most significant at 24 h after UVA irradiation. There was significant difference compared with that at 48 h and 72 h after the same UVA dosage (P<0.01).
UVA can inhibit the proliferation activity of human skin fibroblasts. It might be related to the up-regulation of iNOS gene expression and the over-secretion of NO induced by UVA.
探讨不同剂量的紫外线A（UVA）对人皮肤成纤维细胞增殖及诱导型一氧化氮合酶（iNOS）/一氧化氮（NO）系统的影响，研究皮肤光老化的机制。
体外培养的正常皮肤成纤维细胞分别用1、5和10 J/cm²的UVA照射。分别采用MTT法、逆转录-聚合酶链反应（RT-PCR）、蛋白质印迹法和格里斯反应检测不同剂量UVA照射后不同时间点人皮肤成纤维细胞的增殖活性、iNOS mRNA/蛋白表达及NO生成。
正常成纤维细胞在72小时内存活率随时间增加。在正常人皮肤成纤维细胞中检测到低水平的iNOS mRNA/蛋白表达和NO生成。但在5和10 J/cm²剂量的UVA照射后的各个时间点，细胞存活率的降低以及iNOS mRNA/蛋白表达和NO生成的增加比同时期对照组和1 J/cm² UVA照射组更显著。存在显著差异（P<0.01或P<0.05），在UVA照射后24小时差异最为显著。与相同UVA剂量照射后48小时和72小时相比有显著差异（P<0.01）。
UVA可抑制人皮肤成纤维细胞的增殖活性。这可能与UVA诱导的iNOS基因表达上调和NO分泌过多有关。
